"use strict";
// from: 
// https://geraintluff.github.io/sha256/

var sha256 = function sha256(ascii: string): string {
    function rightRotate(value: any, amount: number) {
        return (value >>> amount) | (value << (32 - amount));
    }
    ;
    var mathPow = Math.pow;
    var maxWord = mathPow(2, 32);
    var lengthProperty: 'length' = 'length';
    var i, j; // Used as a counter across the whole file
    var result: string = '';
    var words: any = [];
    var asciiBitLength = ascii[lengthProperty] * 8;
    //* caching results is optional - remove/add slash from front of this line to toggle
    // Initial hash value: first 32 bits of the fractional parts of the square roots of the first 8 primes
    // (we actually calculate the first 64, but extra values are just ignored)
    var hash = (sha256 as any).h = (sha256 as any).h || [];
    // Round constants: first 32 bits of the fractional parts of the cube roots of the first 64 primes
    var k = (sha256 as any).k = (sha256 as any).k || [];
    var primeCounter = k[lengthProperty];
    /*/
    var hash = [], k = [];
    var primeCounter = 0;
    //*/
    var isComposite: any = {};
    for (var candidate = 2; primeCounter < 64; candidate++) {
        if (!isComposite[candidate]) {
            for (i = 0; i < 313; i += candidate) {
                isComposite[i] = candidate;
            }
            hash[primeCounter] = (mathPow(candidate, .5) * maxWord) | 0;
            k[primeCounter++] = (mathPow(candidate, 1 / 3) * maxWord) | 0;
        }
    }
    ascii += '\x80'; // Append Ƈ' bit (plus zero padding)
    while (ascii[lengthProperty] % 64 - 56)
        ascii += '\x00'; // More zero padding
    for (i = 0; i < ascii[lengthProperty]; i++) {
        j = ascii.charCodeAt(i);
        if (j >> 8) throw new Error('ASCII check failed');
        words[i >> 2] |= j << ((3 - i) % 4) * 8;
    }
    words[words[lengthProperty]] = ((asciiBitLength / maxWord) | 0);
    words[words[lengthProperty]] = (asciiBitLength);
    // process each chunk
    for (j = 0; j < words[lengthProperty];) {
        var w = words.slice(j, j += 16); // The message is expanded into 64 words as part of the iteration
        var oldHash = hash;
        // This is now the undefinedworking hash", often labelled as variables a...g
        // (we have to truncate as well, otherwise extra entries at the end accumulate
        hash = hash.slice(0, 8);
        for (i = 0; i < 64; i++) {
            // Expand the message into 64 words
            // Used below if 
            var w15 = w[i - 15], w2 = w[i - 2];
            // Iterate
            var a = hash[0], e = hash[4];
            var temp1 = hash[7]
                + (rightRotate(e, 6) ^ rightRotate(e, 11) ^ rightRotate(e, 25)) // S1
                + ((e & hash[5]) ^ ((~e) & hash[6])) // ch
                + k[i]
                // Expand the message schedule if needed
                + (w[i] = (i < 16) ? w[i] : (w[i - 16]
                    + (rightRotate(w15, 7) ^ rightRotate(w15, 18) ^ (w15 >>> 3)) // s0
                    + w[i - 7]
                    + (rightRotate(w2, 17) ^ rightRotate(w2, 19) ^ (w2 >>> 10)) // s1
                ) | 0);
            // This is only used once, so *could* be moved below, but it only saves 4 bytes and makes things unreadble
            var temp2 = (rightRotate(a, 2) ^ rightRotate(a, 13) ^ rightRotate(a, 22)) // S0
                + ((a & hash[1]) ^ (a & hash[2]) ^ (hash[1] & hash[2])); // maj
            hash = [(temp1 + temp2) | 0].concat(hash); // We don't bother trimming off the extra ones, they're harmless as long as we're truncating when we do the slice()
            hash[4] = (hash[4] + temp1) | 0;
        }
        for (i = 0; i < 8; i++) {
            hash[i] = (hash[i] + oldHash[i]) | 0;
        }
    }
    for (i = 0; i < 8; i++) {
        for (j = 3; j + 1; j--) {
            var b = (hash[i] >> (j * 8)) & 255;
            result += ((b < 16) ? 0 : '') + b.toString(16);
        }
    }
    return result;
};

export {sha256};
